1. Field of the Invention
The present invention is in the field of automatic washing machines employing vertical axis agitators which oscillate to provide a generally toroidal rollover motion to clothes and wash fluid within the machine, and is particularly pertinent to those agitator constructions useful with large or heavy clothes loads for improving the rollover movement of clothes within the machine to promote uniform soil removal from all portions of the clothes and fabrics undergoing washing.
Maximum clothes rollover is desired to expose all portions of the wash load to adequate scrubbing action. With relatively small to medium wash loads a conventional agitator will cause sufficient clothes movement during washing to achieve satisfactory relatively uniform washing of the clothes.
However, with relatively large wash loads the clothes and fabrics tend to bunch up in the washer basket and adequate circulation of the clothes is prevented. Thus only parts of the load are exposed to effective scrubbing action. This results in a non-uniform washing result with parts of the clothing becoming clean while other parts not exposed to scrubbing action of the agitator remain soiled.
2. The Prior Art
This application is related to co-pending application Ser. No. 696,746, filed June 16, 1976, now U.S. Pat. No. 4,068,053 issued Jan. 17, 1978 which was a continuation-in-part of application Ser. No. 595,792, filed July 14, 1975, now U.S. Pat. No. 3,987,651, which was in turn a continuation of application Ser. No. 418,378, filed Nov. 23, 1973 and now abandoned.
It has been discovered that for effective, uniform soil removal a very efficient movement pattern for clothes and/or fabrics undergoing washing within an automatic, vertical washing machine is one of toroidal rollover. For example, such rollover action may be effected by moving the clothes down adjacent the agitator barrel, radially outwardly from the oscillating agitator vanes in the bottom of the wash basket, upwardly along the wall of the basket, and inwardly to the barrel at the surface of the wash fluid, forming a toroidal pattern in the wash basket.
U.S. Pat. Nos. 3,987,508 and 3,987,651 have recently been issued to one of the present inventors and the assignee of the present application for an apparatus and a method for washing clothes, respectively. Both patents disclose structures employing two-part agitators including an upper auger portion which rotates unidirectionally and an oscillating lower portion having vertically-oriented scrubbing vanes. U.S. Pat. No. 3,987,652 issued to the assignee of the present application, also discloses a two-part agitator system for achieving improved roll-over of large loads of clothing in an automatic washer. When the washing basket is heavily loaded with clothes, the load tends to crowd the agitator and basket and may interfere with efficient rollover action. In machines using conventional agitators which do not include the rollover features of the above mentioned patents, the agitator tends to scrub only the bottom portion of the tightly packed load, that is the portion contacted by the scrubbing vanes on the skirt, resulting in a very poor and uneven washing action.
U.S. Pat. No. 1,806,982 discloses an automatic washer having an oscillating agitator and a horizontal disk which is unidirectionally rotated in the bottom of the clothes washing basket. Rotation of the disk creates upward jets of water from scoops on the disk, aiding in clothes rollover. U.S. Pat. No. 1,635,402 similarly employs upwardly directed water jets at the lower periphery of the clothes basket to aid in clothes rollover.
U.S. Pat. Nos. 2,192,758 and 3,029,623 disclose automatic washing machines having inwardly extending flow-directing baffles mounted on the side walls of the clothes container. U.S. Pat. Nos. 1,665,959, 1,810,047 and 2,230,477 disclose various forms of oscillating agitators having asymmetric vane surfaces.